Introduction. Rapid increase of aged population has been one of major issue affecting national health care plan in Japan. In 2006, Japanese Orthopaedic Association proposed the clinical entity of musculoskeletal ambulation disorder symptom complex (MADS) to define the elderly population with high risk of fall and ambulatory disability caused by musculoskeletal disorders. Osteoarthritis of the knee is one of major cause of MADS. The number of patients with MADS underwent total knee arthroplasty (TKA) had been increased in Japan, and also expected to increase worldwide in the near future. The effectiveness of TKA for the patient with MADS has not been well evaluated. In the present study, we analyzed the early
As the aging society progresses rapidly in Japan, the number of elderly patients underwent TKA is increasing. These elderly patients do not expect to do sports, but regain independency in the activity of daily living. Therefore, we measured basic ambulatory function quantitatively using 3m timed up and go (TUG) test. We clinically experienced patient with medially unstable knee after TKA was more likely to result in the unsatisfactory outcome. We hypothesized that post-operative knee stability influenced ambulatory function recovery after TKA. In this study, we evaluated ambulatory function and knee stability quantitatively, and analyzed the effect of knee stability on the ambulatory function recovery after TKA. Seventy nine patients with varus type osteoarthritic knees underwent TKA were subjected to this study. The mean age of surgery was 72.4 years old. Preoperative standing coronal deformity was 9.6 degrees in varus. TUG test results in less duration with faster ambulatory function. TUG (seconds) was measured at 3 time periods; pre-operatively, at hospital discharge and 1year after surgery. To standardize TUG recovery time during 1 year after TKA, we defined TUG recovery rate as the percentage of recovery time to the pre-operative TUG as shown in the following equation. TUG recovery rate (%) = (TUG pre-op –TUG 1y po) / TUG pre-op ×100 We also evaluated the knee stability at hospital discharge and 1year after surgery. The knee stability at extension and flexion were assessed by varus and valgus stress radiography using Telos (10kg) and stress epicondylar view with 1.5kg weight at the ankle respectively. Image analyzing software was used to measure joint separation distance (mm) at medial as medial joint opening (MJO) and at lateral as lateral joint opening (LJO) at both knee extension and flexion. (Fig.1) The sequential change of TUG was analyzed using repeated measures ANOVA (p<0.05). The influence of joint opening distances (MJO and LJO at extension and flexion) on TUG 1y po and TUG recovery rate were analyzed using simple linear regression analysis (p<0.05).Objective
Materials & Methods